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Post by Dicky the Rockhunter on Aug 15, 2009 19:49:12 GMT -5
 At our show toay a miner brought the below in and we cant seem to figure it out -- any ideas. when is gets totaly dry it turns to a white powder. Comes in green , yellow, pink . Bubbles well in acid.ttotaly disloves in water about 7 hours. Has no smell. Is soft and fragile. Is in old goldmines at at least 500 foot depth. Someone suggested Gothite but we prety much dont think so. Oh well here it is!!  
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Post by hydrogeologist on Aug 16, 2009 9:45:56 GMT -5
Calcium carbonate. Hence the bubbling in acid. I've seen a lot of calcium stalagtitic formations in old mines and even on the underside of concrete overpasses around the Baltimore/DC area. Just goes to show you that minerals are still forming all around us.
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Post by eriktheawful on Aug 18, 2009 5:15:44 GMT -5
I agree... believe it or not I see little mini stalactites and "tree ears" of CaC03 form on the insides of really old leaky ice machines that I fix. Also explains why I rarely have ice out.
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Post by 4cornersrocks on Aug 18, 2009 23:55:54 GMT -5
I was thinking about this today and also came up with calcium carbonate. Carbonic acid leaches its way down through limestone, forming vugs, caves, and CaCo3.
I was building rock walls all summer for this guy out if Texas limestone and we found some really neat stuff. One rock looked like octopus tentacles that were hollow filled with calcite crystals. When I was a kid we used to go to a power substation next to my friends house and find tons of marine fossils in the crushed limestone.
Most of the caves in Texas are full of these formations.
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Post by traveler on Aug 19, 2009 7:47:01 GMT -5
Is it just me or is that a 30 year old picture of Clint Eastwood?
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Post by arappaho on Aug 19, 2009 8:17:08 GMT -5
The hat's just not quite right, traveler.
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